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1.
J Hazard Mater ; 421: 126774, 2022 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-34364214

RESUMEN

Waste furniture boards (WFBs) contain hazardous formaldehyde and volatile organic compounds when left unmanaged or improperly disposed through landfilling and open burning. In this study, pyrolysis was examined as a disposal and recovery approach to convert three types of WFBs (i.e., particleboard, plywood, and fiberboard) into value-added chemicals using thermogravimetric analysis coupled with Fourier-transform infrared spectrometry (TG-FTIR) and pyrolysis coupled with gas chromatography/mass spectrometry (Py-GC/MS). TG-FTIR analysis shows that pyrolysis performed at an optimum temperature of 250-550 °C produced volatile products mainly consisting of carbon dioxide, carbon monoxide, and light hydrocarbons, such as methane. Py-GC/MS shows that pyrolysis at different final temperatures and heating rates recovered mainly phenols (25.9-54.7%) for potential use as additives in gasoline, colorants, and food. The calorific value of WFBs ranged from 16 to 18 MJ/kg but the WFBs showed high H/C (1.7-1.8) and O/C (0.8-1.0) ratios that provide low chemical energy during combustion. This result indicates that WFBs are not recommended to be burned directly as fuel, however, they can be pyrolyzed and converted into solid pyrolytic products such as biochar with improved properties for fuel application. Hazardous components, such as cyclopropylmethanol, were removed and converted into value-added compounds, such as 1,4:3,6-dianhydro-d-glucopyranose, for use in pharmaceuticals. These results show that the pyrolysis of WFBs at high temperature and low heating rate is a promising feature to produce value-added chemicals and reduce the formation of harmful chemical species. Thus, the release of hazardous formaldehyde and greenhouse gases into the environment is redirected.


Asunto(s)
Diseño Interior y Mobiliario , Pirólisis , Calor , Metano , Temperatura
2.
J Hazard Mater ; 421: 126819, 2022 01 05.
Artículo en Inglés | MEDLINE | ID: mdl-34396960

RESUMEN

This study investigated the dosage-effect of biochar on the suppressed mesophilic digestion of oily sludge (OS) containing naphthalene (recalcitrant compound) and starch (easily bioavailable substrate). Methanogenesis was inhibited in control with OS, where biomethane yield (63.33 mL/gVS) was obviously lower than theoretical yield (260.55 mL/gVS). With adding optimal dose of biochar (0.60 g/gVS OS), the highest CH4 yield (138.41 mL/gVS) was 2.19 times of control. Meanwhile, the efficiencies of hydrolysis, acidogenesis and acetogenesis were significantly enhanced. However, excessive biochar (4.80 g/gVS OS) caused negative effects with methanogenic efficiency diminished by 32.5% and lag phase prolonged by 5.72 h. Dissolved organic matter (DOM) analysis showed that humic acid-like and fulvic acid-like components percentages of fluorescence regional integration were decreased because of the adsorption of biochar. In addition, biochar mediating interspecies electron transfer selectively enriched electroactive fermentation bacteria (Clostridium and Bacteroides) and acetoclastic Methanosaeta, which was responsible for promoting mesophilic digestion performance. The functional genes related to metabolism and environmental information processing were potentially activated by biochar. Above results indicate that moderate biochar application may mitigate the bio-toxicity suppression of OS, which help to provide a promising pathway for reinforcing oily wastes bio-treatment.


Asunto(s)
Microbiota , Aguas del Alcantarillado , Anaerobiosis , Reactores Biológicos , Carbón Orgánico , Metano
3.
J Environ Manage ; 301: 113853, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34624575

RESUMEN

Olive mill wastewater, a by-product of olive oil production after the operation of three-phase decanters, was used in a thermophilic anaerobic digester targeting efficient bioconversion of its organic load into biogas. An active anaerobic inoculum originating from a mesophilic reactor, was acclimatized under thermophilic conditions and was filled into a high-rate upflow packed bed reactor. Its performance was tested towards the treatment efficacy of olive mill wastewater under thermophilic conditions reaching the minimum hydraulic retention time of 4.2 d with promising results. As analysis of the microbial communities is considered to be the key for the development of anaerobic digestion optimization techniques, the present work focused on characterizing the microbial community and its variation during the reactor's runs, via 16S rRNA amplicon sequencing. Identification of new microbial species and taxonomic groups determination is of paramount importance as these representatives determine the bioprocess outcome. The current study results may contribute to further olive mill wastewater exploitation as a potential source for efficient biogas production.


Asunto(s)
Reactores Biológicos , Aguas Residuales , Anaerobiosis , Biocombustibles , Metano , ARN Ribosómico 16S/genética
4.
J Environ Manage ; 301: 113914, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34628280

RESUMEN

Humic acid (HA) is an important active compound formed during anaerobic digestion process, with a complex structure and dynamic electron transfer capacity (ETC). However, the mechanisms by which these macromolecular organic compounds dynamically interact with the microbial anaerobic digestion process at different operating temperatures are still unclear. In this study, the link between the evolution of the ETC of HAs and the microbial community under mesophilic and thermophilic conditions was investigated. The results showed an increasing trend in the ETC of HAs in both mesophilic (671-1479 µmol gHA-1) and thermophilic (774-1506 µmol gHA-1) anaerobic digestion (AD) until day 25. The ETC was positively correlated with the bacterial community of hydrolytic and acidogenic phases, but negatively correlated with the archaeal community of the methanogenic phase. Furthermore, the relationship between ETC and key enzyme activity was explored using a co-occurrence network analysis. HAs revealed a high potential to promote key enzyme activities during hydrolysis (amylase and protease) and acidification (acetate kinase, butyrate kinase, and phosphotransacetylase) while inhibiting the key enzyme activity in the methanogenic phase during the anaerobic digestion process. Moreover, HAs formed under thermophilic conditions had a greater influence on key enzyme activities than those formed under mesophilic conditions. This study advances our understanding of the mechanisms underlying the influence of HAs on anaerobic digestion performance.


Asunto(s)
Euryarchaeota , Sustancias Húmicas , Anaerobiosis , Reactores Biológicos , Electrones , Metano , Aguas del Alcantarillado , Temperatura
5.
J Environ Manage ; 301: 113882, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34638040

RESUMEN

Due to its increasing demands for fossil fuels, Indonesia needs an alternative energy to diversify its energy supply. Landfill gas (LFG), which key component is methane (CH4), has become one of the most attractive options to sustain its continued economic development. This exploratory study seeks to demonstrate the added value of landfilled municipal solid waste (MSW) in generating sustainable energy, resulting from CH4 emissions in the Bantargebang landfill (Jakarta). The power generation capacity of a waste-to-energy (WTE) plant based on a mathematical modeling was investigated. This article critically evaluated the production of electricity and potential income from its sale in the market. The project's environmental impact assessment and its socio-economic and environmental benefits in terms of quantitative and qualitative aspects were discussed. It was found that the emitted CH4 from the landfill could be reduced by 25,000 Mt annually, while its electricity generation could reach one million kW â‹…h annually, savings on equivalent electricity charge worth US$ 112 million/year (based on US' 8/kW ⋅ h). An equivalent CO2 mitigation of 3.4 × 106 Mt/year was obtained. The income from its power sale were US$ 1.2 ×106 in the 1st year and 7.7 ×107US$ in the 15th year, respectively, based on the projected CH4 and power generation. The modeling study on the Bantargebang landfill using the LFG extraction data indicated that the LFG production ranged from 0.05 to 0.40 m3 per kg of the landfilled MSW. The LFG could generate electricity as low as US' 8 per kW ⋅ h. With respect to the implications of this study, the revenue not only defrays the cost of landfill's operations and maintenance (O&M), but also provides an incentive and means to further improve its design and operations. Overall, this work not only leads to a diversification of primary energy, but also improves environmental protection and the living standard of the people surrounding the plant.


Asunto(s)
Gases de Efecto Invernadero , Eliminación de Residuos , Electricidad , Humanos , Indonesia , Metano/análisis , Residuos Sólidos/análisis , Instalaciones de Eliminación de Residuos
6.
J Environ Manage ; 301: 113927, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34638043

RESUMEN

The study demonstrates a two-stage integrated process for bio-methanol production using Methylosinus trichosporium NCIMB 11131, coupled with sequestration of methane and carbon dioxide. The first stage involved generation of methanotrophic biomass via sequestration of methane; which was used as biocatalyst to reduce carbon dioxide into methanol in the second stage. Maximum biomass titer of 3.39 g L-1 and productivity of 0.60 g L-1 d-1 were achieved in semi-batch stirred tank reactor with methane concentration in the inlet gas mixture of 2.5% v/v and gas flow rate of 0.5 vvm. Methane fixation rate was estimated to be 0.32 g L-1 d-1. Maximum methanol titer of 0.58 g L-1 was achieved at headspace carbon dioxide concentration of 50% v/v and liquid to headspace volume ratio 10:90. Subsequently, a kinetic model was developed to predict and understand the system behaviour in terms of dynamic profile of growth, methanol formation, concentration of dissolved methane or carbon dioxide in the aqueous phase and headspace carbon dioxide concentration, in response to varying process parameters. The model can serve as a tool for estimation of process parameters and aid in overall production optimization.


Asunto(s)
Metano , Methylosinus trichosporium , Biomasa , Dióxido de Carbono , Metanol
7.
Sci Total Environ ; 803: 150008, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34482130

RESUMEN

The intensifying globalization contributes to the anthropogenic methane (CH4) emissions outsourcing, a strong greenhouse gas and harmful air pollutant, through the increasingly complex global trade network. However, the CH4 flow patterns embodied in global traded goods and services have not been interpreted from the perspective of a complex network. In this paper, we integrate global CH4 emission inventory from the EDGAR (the Emission Database for Global Atmospheric Research) databases, global multi-regional input-output model from the GTAP database, and complex network analysis to reveal the structural characteristics of the global CH4 flow network (GCFN). In the GCFN, more than one quarter of the global anthropogenic CH4 emissions in 2014 are associated with international trade. The top 20 economies contribute to about 70% of the total embodied CH4 emission flows. The GCFNs mainly consist of tripartite patterns centered on China, the USA and Russia. Some emerging countries, such as Thailand and Brazil, also exhibit dominated positions in different kinds of GCFNs. Moreover, the core-periphery structure of the GCFN confirms the existence of a few hub economies associated with a large amount of CH4 emissions. The results emphasize the multinational cooperation on global CH4 emission mitigation, and well-focused mitigation policies should be implemented on some key economies.


Asunto(s)
Gases de Efecto Invernadero , Servicios Externos , Comercio , Internacionalidad , Metano/análisis
8.
Sci Total Environ ; 803: 149577, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34487896

RESUMEN

Forested coastal wetlands are globally important systems sequestering carbon and intercepting nitrogen pollution from nutrient-rich river systems. Coastal wetlands that have suffered extensive disturbance are the target of comprehensive restoration efforts. Accurate assessment of restoration success requires detailed mechanistic understanding of wetland soil biogeochemical functioning across restoration chrono-sequences, which remains poorly understood for these sparsely investigated systems. This study investigated denitrification and greenhouse gas fluxes in mangrove and Melaleuca forest soils of Vietnam, using the 15N-Gas flux method. Denitrification-derived N2O was significantly higher from Melaleuca than mangrove forest soils, despite higher potential rates of total denitrification in the mangrove forest soils (8.1 ng N g-1 h-1) than the Melaleuca soils (6.8 ng N g-1 h-1). Potential N2O and CO2 emissions were significantly higher from the Melaleuca soils than from the mangrove soils. Disturbance and subsequent recovery had no significant effect on N biogeochemistry except with respect to the denitrification product ratio in the mangrove sites, which was highest from the youngest mangrove site. Potential CO2 and CH4 fluxes were significantly affected by restoration in the mangrove soils. The lowest potential CO2 emissions were observed in the mid-age plantation and potential CH4 fluxes decreased in the older forests. The mangrove system, therefore, may remove excess N and improve water quality with low greenhouse gas emissions, whereas in Melaleucas, increased N2O and CO2 emissions also occur. These emissions are likely balanced by higher carbon stocks observed in the Melaleuca soils. These mechanistic insights highlight the importance of ecosystem restoration for pollution attenuation and reduction of greenhouse gas emissions from coastal wetlands. Restoration efforts should continue to focus on increasing wetland area and function, which will benefit local communities with improved water quality and potential for income generation under future carbon trading.


Asunto(s)
Gases de Efecto Invernadero , Dióxido de Carbono/análisis , Desnitrificación , Ecosistema , Monitoreo del Ambiente , Gases de Efecto Invernadero/análisis , Metano/análisis , Óxido Nitroso/análisis , Suelo , Humedales
9.
Sci Total Environ ; 803: 150035, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34500275

RESUMEN

The Loess Plateau is China's primary apple-growing area, and the orchard is a significant source of greenhouse gases (GHGs) emissions due to high nitrogen fertilizer input. Thus, a two-year field study was carried out to investigate the effects of apple wood derived biochar on GHGs emissions during apple orchard production, including soil organic carbon sequestration (SOCSR) and net global warming potential (NGWP) assessments. There are four treatments in this study: 20 t ha-1 biochar in a non-fertilized plot (B); no biochar in a fertilized plot (F); 20 t ha-1 biochar in a fertilized plot (FB); no biochar in a non-fertilized plot (CK). Results showed that the combined application of biochar and fertilizer stimulated CO2 emissions by 9.25% and 8.39% than either biochar or fertilizer alone. Meanwhile, biochar in fertilized plot increased annual N2O emissions by 32.6% as compared to fertilized plot without biochar amendment. Compared with CK, biochar had no significant effect on GHG emissions in unfertilized plot. The N2O emission factor of FB and F were 0.91% and 0.45% respectively in 2017-2018 and they were both 0.34% in 2018-2019. Moreover, compared with CK, the FB and B treatments increased the SOCSR by 316.52% and 354.78%, while, decreased the NGWP by 368.93% and 480.91%, respectively. Thus, biochar application may help reduce the impact of apple production on climate change by sequestering more soil organic carbon and decreasing the NGWP.


Asunto(s)
Malus , Suelo , Agricultura , Carbono , Dióxido de Carbono/análisis , Secuestro de Carbono , Carbón Orgánico , China , Calentamiento Global , Metano/análisis , Óxido Nitroso/análisis
10.
Spectrochim Acta A Mol Biomol Spectrosc ; 266: 120418, 2022 Feb 05.
Artículo en Inglés | MEDLINE | ID: mdl-34600325

RESUMEN

We report the development of a compact near-infrared (NIR) laser-based trace methane (CH4) detection system. This detection system relied on a 2334 nm distributed feedback (DFB) fiber laser as the light source. A parallel dense light-spot pattern multipass gas cell (MGC) with 41.5 m effective absorption path length was utilized to improve the system sensitivity. A self-calibration approach based on direct absorption spectroscopy (DAS) calibrated wavelength modulation spectroscopy (WMS) technique was employed to solve the problem of extra concentration calibration requirement in traditional WMS technique, and to improve the accuracy and stability of the system. According to the Allan deviation analysis, 1-s measurement precision of 0.61 ppmv for DAS and 0.16 ppmv for WMS was obtained, which could be further reduced to 0.11 ppmv for DAS and 0.03 ppmv for WMS by averaging up to 80 s and 50 s, respectively. A week-long continuous atmospheric CH4 concentration measurement was also carried out to demonstrate the long-term performance of our CH4 detection system. With a fast dynamic response characteristics, high-accuracy and high-sensitivity, the proposed detection system is suitable for CH4 measurement in many fields such as atmospheric chemistry analyzation, industrial safety monitoring, agricultural information acquisition, etc.


Asunto(s)
Rayos Láser , Metano
11.
Sci Total Environ ; 803: 150131, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34788940

RESUMEN

Microbial communities from rhizosphere (rhizomicrobiomes) have been significantly impacted by domestication as evidenced by a comparison of the rhizomicrobiomes of wild and related cultivated rice accessions. While there have been many published studies focusing on the structure of the rhizomicrobiome, studies comparing the functional traits of the microbial communities in the rhizospheres of wild rice and cultivated rice accessions are not yet available. In this study, we used metagenomic data from experimental rice plots to analyze the potential functional traits of the microbial communities in the rhizospheres of wild rice accessions originated from Africa and Asia in comparison with their related cultivated rice accessions. The functional potential of rhizosphere microbial communities involved in alanine, aspartate and glutamate metabolism, methane metabolism, carbon fixation pathways, citrate cycle (TCA cycle), pyruvate metabolism and lipopolysaccharide biosynthesis pathways were found to be enriched in the rhizomicrobiomes of wild rice accessions. Notably, methane metabolism in the rhizomicrobiomes of wild and cultivated rice accessions clearly differed. Key enzymes involved in methane production and utilization were overrepresented in the rhizomicrobiome samples obtained from wild rice accessions, suggesting that the rhizomicrobiomes of wild rice maintain a different ecological balance for methane production and utilization compared with those of the related cultivated rice accessions. A novel assessment of the impact of rice domestication on the primary metabolic pathways associated with microbial taxa in the rhizomicrobiomes was performed. Results indicated a strong impact of rice domestication on methane metabolism; a process that represents a critical function of the rhizosphere microbial community of rice. The findings of this study provide important information for future breeding of rice varieties with reduced methane emission during cultivation for sustainable agriculture.


Asunto(s)
Oryza , Domesticación , Metano , Oryza/genética , Fitomejoramiento , Rizosfera
12.
Chemosphere ; 286(Pt 1): 131650, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34325261

RESUMEN

Hydrogen sulfide (H2S) can influence methanotrophic activities and be adsorbed by biochar (BC); however, the impact of H2S on BC in stimulating the methane (CH4) oxidation capacity of landfill cover soil (LCS) has not been clarified. Thus, batch incubation experiments were conducted to observe the effect of H2S on the CH4 oxidation capacity of and microbial communities in BC-amended LCS. Three landfill gas conditions were considered: 5 % CH4 and 15 % oxygen (O2) (5 M), 10 % CH4 and 10 % O2, and 20 % CH4 and 5 % O2 (20 M) by volume, with H2S concentrations of 0, 100, 250, and 1000 ppm, respectively. Another series was conducted using LCS subjected to pre-H2S saturation under the 20 M gas condition. In the 5 M gas condition suitable for the dominant methanotroph Methylocaldum (type I), the BC retained its ability to stimulate the CH4 oxidation capacity of LCS (enhancement of 41-108 %) in the presence of H2S. Additionally, when H2S ≤ 250 ppm, the BC exhibited a relatively consistent impact of H2S on both CH4 oxidation capacity and microbial communities in LCS, independent of the CH4 or O2 concentrations. This result could be attributed to the different pathways of H2S metabolism for the LCS and BC-amended LCS. Furthermore, when saturated adsorption of H2S occurred for the LCS, the CH4 oxidation capacity for BC-amended LCS was higher than that for non-amended LCS, which demonstrated the ability of BC in alleviating the inhibition of H2S on CH4 oxidation due to its excellent H2S adsorption under even anoxic environments.


Asunto(s)
Sulfuro de Hidrógeno , Microbiota , Carbón Orgánico , Metano , Suelo , Instalaciones de Eliminación de Residuos
13.
Chemosphere ; 286(Pt 2): 131763, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34352552

RESUMEN

Typical large-scale sewage-water treatments consume energy, occupy space and are unprofitable. This work evaluates a conceivable two-staged sewage-water treatment at 40,000 m3/d of sewage-water with sewage-sludge (totaling 10kgCOD/m3) that becomes a profitable bioenergy producer exporting reusable water and electricity, while promoting carbon capture. The first stage comprises microbial anaerobic digesters reducing the chemical oxygen demand (COD) by 95% and producing 60%mol methane biogas. The effluent waters enter the subsequent aerobic stage comprising microbial air-fed digesters that extend COD reduction to 99.7%. To simulate the process, up-to-date anaerobic/aerobic digester models were implemented. A biogas-combined-cycle power plant with/without post-combustion carbon capture is designed to match the biogas production, supplying electricity to the process and to the grid. Results comprehend electricity exportation of 13.21 MW (7.92 kWh/tReusable-Water) with -9.957tCO2/h of negative carbon emission (-0.6 kgCO2-Emitted/kgCOD-Removed). The biogas-combined-cycle without carbon capture achieves 21.08 MW of power exportation, while a 37.3% energy penalty arises if carbon capture is implemented. Configurations with/without carbon capture reach feasibility at 125 USD/MWh of electricity price, with respective net present values of 6.86 and 85.07 MMUSD and respective payback-times of 39 and 12 years. These results demonstrate that large-scale sewage-water treatment coupled to biogas-fired combined-cycles and carbon capture can achieve economically feasible bioenergy production with negative carbon emissions.


Asunto(s)
Aguas del Alcantarillado , Purificación del Agua , Anaerobiosis , Biocombustibles/análisis , Reactores Biológicos , Carbono , Metano , Eliminación de Residuos Líquidos
14.
Chemosphere ; 286(Pt 2): 131774, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34365172

RESUMEN

This study reports an alternative method for black liquor treatment with potential for energy and process savings in the paper and pulp industry. Gasification of black liquor was carried out under sub- and supercritical conditions, varying the black liquor feed composition (0.10, 2.55 and 5.00 wb%) and temperature (350, 425 and 500 °C). Liquid products were identified by high resolution mass spectrometry (FT-Orbitrap MS) and compounds belonging to classes O3 and O4 were found to be the most representative in the products of reactions performed at 500 °C. The mass spectra results also revealed the overall selectivity of reactions, where decarboxylation and demethoxylation reactions were favored under subcritical and supercritical conditions, respectively. Among the gaseous products, hydrogen and methane were produced with maximum of 69.04 and 28.75 mol%, respectively, at 2.55 wb% and 425 °C. The proposed thermodynamic modelling of the reaction system satisfactorily predicted the gas phase behavior of the system. In the economic analysis, the simulated conditions indicated that the main energy requirements for a scaled-up black liquor gasification process are related to the necessary heat exchangers and pressurizing of the black liquor solution. Furthermore, the cost of the black liquor gasification is around 0.06 US$ per kg of feed stream. Liquid and gaseous products from gasification could be obtained at a cost of 56.64 US$ and 3.35 US$ per tonne of stream, respectively. Therefore, black liquor gasification is an interesting route for obtaining combustible gases and value-added bioproducts.


Asunto(s)
Gases , Metano , Hidrógeno , Temperatura , Termodinámica , Agua
15.
Chemosphere ; 286(Pt 3): 131840, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34399267

RESUMEN

Anaerobic digestion technology has been widely used because it has a unique advantage of producing biogas as a renewable energy source. Therefore, several methods were studied to facilitate anaerobic methane production process. Coupling direct voltage and single conductive particles was an effective method to improve anaerobic wastewater treatment efficiency and methane production. However, the enhancement method was limited in this process due to the current of direct voltage or the toxicity of nanoparticles. Therefore, the granular activated carbon loaded with nanoscale zero valent iron (GAC-NZVI) particles prepared by co-precipitation method were added to the anaerobic synthetic wastewater system with direct voltage (0.10 V) to improve the treatment efficiency in this study. GAC-NZVI particles were added into anaerobic system with 0.10 V direct voltage to enhance CH4 production process. The COD removal and total CH4 production were enhanced by 4.22 % and 10.83 % with GAC-NZVI particles. The measurement results of EPS and Fe concentration showed that GAC-NZVI particles promoted the secretion of EPS by microorganisms, which could improve the floc strength of granular sludge. The measurements of conductivity and cyclic voltammetry (CV) showed that particles accelerated the metabolism of microorganism and promoted the electron transfer process. The increasing of Methanothrix and Methanobacterium could strengthen the methanogenesis. The abundances of bacteria and archaea using indirect interspecies electron exchange form (such as H2 or formate transfer microorganisms) were decreased after adding the particles. The results indicated that anaerobic treatment efficiency could be enhanced under the combined action of direct voltage and particles.


Asunto(s)
Carbón Orgánico , Hierro , Anaerobiosis , Reactores Biológicos , Metano , Aguas del Alcantarillado
16.
Chemosphere ; 286(Pt 3): 131835, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34426273

RESUMEN

This paper proposed to interpret the novel method of extracellular polymeric substance (EPS) removal in advance to sludge disintegration to enrich bioenergy generation. The sludge has been subjected to deflocculation using Zinc oxide/Chitosan nanocomposite film (ZCNF) and achieved 98.97% of solubilization which enhance the solubilization of organics. The obtained result revealed that higher solubilization efficiency of 23.3% was attained at an optimal specific energy of 2186 kJ/kg TS and disintegration duration of 30 min. The deflocculated sludge showed 8.2% higher solubilization than the flocculated sludge emancipates organics in the form of 1.64 g/L of SCOD thereby enhancing the methane generation. The deflocculated sludge produces methane of 230 mL/g COD attained overall solid reduction of 55.5% however, flocculated and control sludge produces only 182.25 mL/g COD and 142.8 mL/g COD of methane. Based on the energy, mass and cost analysis, the deflocculated sludge saved 94.1% of energy than the control and obtained the net cost of 5.59 $/t which is comparatively higher than the flocculated and control sludge.


Asunto(s)
Quitosano , Nanocompuestos , Óxido de Zinc , Anaerobiosis , Análisis de la Demanda Biológica de Oxígeno , Conservación de los Recursos Energéticos , Matriz Extracelular de Sustancias Poliméricas , Floculación , Metano , Aguas del Alcantarillado , Eliminación de Residuos Líquidos
17.
Chemosphere ; 286(Pt 3): 131929, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-34463260

RESUMEN

Sustainable sewage treatment plants (STPs) have been intensively investigated in search for low-cost, environmental-friendly options. Anaerobic-aerobic treatment solutions, as upflow anaerobic sludge blanket (UASB) reactors followed by high rate algal ponds (HRAP) have already proved to be efficient for pollutants and micropollutants removal, as well as for energy recovery from the co-digestion of raw sewage and microalgal biomass. Since microalgae cells have complex structures that make them resistant to anaerobic digestion, pre-treatment techniques may be applied to improve microalgal biomass solubilisation and methane yield. Among the thermal pre-treatments, the use of solar energy for biomass solubilisation has yet to be investigated. Therefore, this study aimed at evaluating the performance of a solar thermal microalgal biomass pre-treatment prior to the anaerobic co-digestion with raw sewage, comparing a UASB reactor feed only raw sewage and other UASB reactor feed with raw sewage and pre-treated microalgal biomass. The results showed that, the solar pre-treatment step reached an organic matter solubilisation of 32% (COD). Furthermore, the methane yield was increased by 45% (from 81 to 117 NL CH4 kg-1 COD), after the anaerobic co-digestion with pre-treated microalgae as compared to the mono-digestion of raw sewage, indicating significant difference between the evaluated UASB reactors. The energy assessment showed a positive energy balance, as the total energy produced was twice the energy consumed in the system.


Asunto(s)
Microalgas , Aguas del Alcantarillado , Anaerobiosis , Biomasa , Reactores Biológicos , Digestión , Metano , Eliminación de Residuos Líquidos
18.
Sci Total Environ ; 803: 150108, 2022 Jan 10.
Artículo en Inglés | MEDLINE | ID: mdl-34525766

RESUMEN

The anaerobic membrane bioreactor (AnMBR) has considerable potential for treating wastewater, although there is very little data on the effect of antibiotics on AnMBR performance. This study examined the effect of Ciprofloxacin (CIP) - an antibiotic that can occur at high concentrations, and has a substantial impact on ecosystems, on AnMBR performance. The long-term (44 days) presence of 0.5 mg/L CIP in the feed did not have a strong effect on COD removal, volatile fatty acid (VFA) accumulation, or methane yield, but did affect the pH, soluble microbial products (SMPs) and suspended solids. However, at 4.7 mg/L CIP, a significant effect on all the parameters tested was seen. 16S rRNA gene-based community analysis demonstrated that CIP changed the phylogenetic structure and altered the species richness and diversity. The relative abundance of various genera was also changed, and this explained much of the change in AnMBR behavior.


Asunto(s)
Ciprofloxacina , Ecosistema , Anaerobiosis , Reactores Biológicos , Membranas Artificiales , Metano , Filogenia , ARN Ribosómico 16S/genética , Aguas del Alcantarillado , Eliminación de Residuos Líquidos , Aguas Residuales
19.
Sci Total Environ ; 802: 149612, 2022 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-34438128

RESUMEN

The application of Anaerobic Membrane Bioreactors (AnMBRs) for municipal wastewater treatment has been made sufficiently sustainable for practical implementations. The potential benefits are significant as AnMBRs effectively remove a broad range of contaminants from wastewater for water reuse, degrade organics in wastewater to yield methane-rich biogas for resultant energy production, and concentrate nutrients for subsequent recovery for fertilizer production. However, there still exist some concerns requiring vigilant considerations to make AnMBRs economically and technically viable. This review paper briefly describes process fundamentals and the basic AnMBR configurations and highlights six major factors which obstruct the way to AnMBRs installations affecting their performance for municipal wastewater treatment: (i) organic strength, (ii) membrane fouling, (iii) salinity build-up, (iv) inhibitory substances, (v) temperature, and (vi) membrane stability. This review also covers the energy utilization and energy potential in AnMBRs aiming energy neutrality or positivity of the systems which entails the requirement to further determine the economics of AnMBRs. The implications and related discussions have also been made on future perspectives of the concurrent challenges being faced in AnMBRs operation.


Asunto(s)
Eliminación de Residuos Líquidos , Purificación del Agua , Anaerobiosis , Reactores Biológicos , Membranas Artificiales , Metano , Aguas del Alcantarillado , Aguas Residuales
20.
Sci Total Environ ; 804: 150147, 2022 Jan 15.
Artículo en Inglés | MEDLINE | ID: mdl-34509840

RESUMEN

Microbial conversion of methane to electricity, fuels, and liquid chemicals has attracted much attention. However, due to the low solubility of methane, it is not considered a suitable substrate for microbial fuel cells (MFCs). In this study, a conductive fiber membrane (CFM) module was constructed as the bioanode of methane-driven MFCs, directly delivering methane. After biofilm formation on the CFM surface, a steady voltage output of 0.6 to 0.7 V was recorded, and the CFM-MFCs obtained a maximum power density of 64 ± 2 mW/m2. Moreover, methane oxidation produced a high concentration of intermediate acetate (up to 7.1 mM). High-throughput 16S rRNA gene sequencing suggests that the microbial community was significantly changed after electricity generation. Methane-related archaea formed a symbiotic consortium with characterized electroactive bacteria and fermentative bacteria, suggesting a combination of three types of microorganisms for methane conversion into acetate and electricity.


Asunto(s)
Fuentes de Energía Bioeléctrica , Acetatos , Electricidad , Electrodos , Metano , ARN Ribosómico 16S/genética
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